麻烦困难问题用英文怎么写

Troublesome or difficult questions can be written in English like this:
- Troublesome issue

• Challenging question
• Problematic inquiry
• Daunting query
• Complex question
• Difficult-to-answer question
• Stump question
• Tricky question
• Thorny issue
• Thoroughbred question

Troublesome or difficult questions can be written in English as:
- A challenging question

• A tricky question
• A hard-to-answer question
• A complex question
• A difficult problem to solve
• An intricate query
• A challenging issue to tackle